Phonon Fit for LESCO 0.125

Generated on: 2025-07-22 11:54:16

Model Description (LaTeX)

Model description

The model is a sum of a pseudo-Voigt elastic peak (fixed mixing), two Gaussian phonon peaks (breathing, bond-buckling), a resolution-convolved DHO magnon, and a linear background:

Individual Components

1. Elastic Peak (Pseudo-Voigt, fixed mixing)

where $\mu = 0.05$ (fixed), $\text{FWHM}_1 = 0.040$ eV (fixed resolution), and: - $L(E, x_1, \text{FWHM}_1) = \frac{(\text{FWHM}_1/2)^2}{(E - x_1)^2 + (\text{FWHM}_1/2)^2}$ (Lorentzian) - $G(E, x_1, \text{FWHM}_1) = \exp\left(-\frac{(E - x_1)^2}{2\sigma_1^2}\right)$ where $\sigma_1 = \frac{\text{FWHM}_1}{2\sqrt{2\ln(2)}}$ (Gaussian)

2. Breathing Mode (Gaussian)

where $\sigma_2 = \frac{\text{FWHM}_2}{2\sqrt{2\ln(2)}}$ and $\text{FWHM}_2 = 0.040$ eV (fixed resolution)

3. Magnon Peak (DHO convolved with Gaussian resolution)

where $\gamma = \frac{FWHM_3}{2}$ (free parameter), and $G_{\text{res}}(E)$ is a Gaussian with FWHM = 0.040 eV (resolution)

4. Bond-buckling Mode (Gaussian)

where $\sigma_4 = \frac{\text{FWHM}_4}{2\sqrt{2\ln(2)}}$, and $\text{FWHM}_4 = 0.040$ eV (fixed resolution)

5. Linear Background

Fixed Parameters

  • Resolution (FWHM) = 0.040 eV for elastic, breathing, and bond-buckling peaks, and for magnon convolution
  • Elastic mixing parameter $\mu = 0.05$ (mostly Gaussian with small Lorentzian component)

Free Parameters

  • Peak positions: $x_1, x_2, x_3, x_4$ (4 parameters)
  • Peak amplitudes: $A_1, A_2, A_3, A_4$ (4 parameters)
  • Magnon FWHM: $\text{FWHM}_3$ (1 parameter)
  • Background slope: slope (1 parameter)
  • Total: 10 free parameters

Parameters and Bounds

Parameter Value
x0_1 (elastic center) [-0.100, 0.100] eV
A_1 (elastic amplitude) [0, 10]
x0_2 (breathing center) [0.050, 0.200] eV
A_2 (breathing amplitude) [0, 10]
x0_3 (magnon center) [0.040, 0.550] eV
A_3 (magnon amplitude) [0, inf]
res_3 (magnon FWHM) [0.040, 10.000] eV
x0_4 (bond-buckling center) [0.015, 0.060] eV
A_4 (bond-buckling amplitude) [0.00, 1.00]
slope (background) [0, 1]

Figures for T = 15 K

Figures

The fit results

The fit results

The phonon dispersion

The phonon dispersion

Phonon intensities

Phonon intensities

Figures for T = 100 K

Figures

The fit results

The fit results

The phonon dispersion

The phonon dispersion

Phonon intensities

Phonon intensities

Figures for T = 150 K

Figures

The fit results

The fit results

The phonon dispersion

The phonon dispersion

Phonon intensities

Phonon intensities

Figures for T = 200 K

Figures

The fit results

The fit results

The phonon dispersion

The phonon dispersion

Phonon intensities

Phonon intensities

Temperature Dependence Comparison

This section compares the temperature dependence of the elastic intensity, breathing intensity, breathing dispersion, bond-buckling intensity, and bond-buckling dispersion for LESCO 0.125.

  • Colors: 15K (blue), 100K (cyan), 150K (gold), 200K (red)
  • Circles: Breathing mode; Squares: Bond-buckling mode; Triangles: Elastic (divided by 1.5)

Figures